Bathing assist device

ABSTRACT

Bathing-assist device to assisting a bather to lower himself or herself into a bathtub for bathing and later to lift himself or herself out of the bathtub, directed at persons who cannot otherwise take a bath without outside assistance. The device uses the hydraulic force available from household water pressure and has no electrical aspects. Further, the device includes a support frame from which the various components are suspended, a frame that can be lifted directly onto a bathtub with which the device is to be used, eliminating the need to affix anything to the bathroom walls or to the bathtub itself.

[0001] This application claims priority from provisional application 60/442,189, filed on Jan. 22, 2003.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to mechanical-assist devices for persons who have physical handicaps. More particularly it relates to such devices directed at persons who, though ambulatory, have difficulty getting in and out of bathtubs. More particularly yet, it relates to such devices powered entirely by hydraulic forces, with no need for electricity, and that are free-standing with no need to be affixed to the bathroom walls or to the bathtub.

[0004] 2. Description of Prior Art

[0005] Devices to assist those with physical limitations of movement can be divided into two categories: those directed at persons who are normally restricted to wheelchairs or gurneys; those directed at persons who are able to walk by themselves but who, because of aging or other restrictions of movement, can no longer engage in activities that they have previously done with ease. It is worth dividing the target audience into these two categories, because apparatus aimed at the first group tends to be much more complicated and controlling than the devices aimed at the second group, members of which may need only a little boost to accomplish the desired task.

[0006] Of the important activities that are easy to do for most of us for the first two-thirds of our lives, but which later become difficult or impossible, getting into and out of a bathtub may top the list. Important for personal hygiene and more efficient and satisfying than a shower, the hot bath often becomes a thing of the past for people as they age and for younger people afflicted by arthritis. Unlike a walk-in shower stall, most bathtubs are designed such that the bather must be able to lift his or her legs high enough to clear a one- to three-foot rim in order to get in the tub. Getting out is even more difficult, as the bather must first rise from a sitting position and then step up and out of the tub. This motion may be impossible for persons who are elderly, have sustained injury to the legs or back, or have muscular, bone, or neurological disorders. This problem of entering and exiting the bathtub is compounded by the presence of wet, slippery surfaces in and around the tub. Thus, getting into and out of the bathtub can for many people be a safety hazard as well as an extreme inconvenience, if not impossibility, even though they have little or no trouble in walking up to the bathtub.

[0007] The importance of enabling persons with physical limitations to enter and exit bathtubs unattended has generated a number of mechanical assist-devices. However, most of these are overdesigned if the target users are people who can walk up to and away from the tub unassisted and unattended. For example, Nowosad (U.S. Pat. No. 6,363,545) describes a “support tub,” having an elastic membrane (mat) extending across its top opening, and initially supported by fluid in the tub. The bather lies down on, or is transferred onto, the mat, after which the volume of a fluid within the support tub is reduced so as to permit the mat to stretch, thereby lowering the supine bather into the tub, while forming a concavity that serves as the bathing tub. When the bath is over, fluid is re-introduced into the support tub, beneath the membrane, which then rises, thereby lifting the bather back to his or her original level. From that point, it is relatively easy to swing around into a seated position and step from the tub, or to be rolled onto a gurney or shifted into a wheelchair. Although providing some of the needed assistance to the bather, the Nowosad device is large and heavy and of limited utility to the persons wishing to retrofit existing bathtubs in ordinary household bathrooms. Furthermore, the Nowosad device merely elevates the bather to the rim of the tub while the bather is still in a supine position. It provides no assistance for allowing the bather to stand up from this position.

[0008] Norton et al. (U.S. Pat. No. 6,055,685) also discloses a bathtub with a membrane across the top opening. In the case of Norton et al., however, the membrane, though flexible, is not stretchable. It is connected to a take-up reel, permitting membrane material to be reversibly fed out, using an electric motor, so as to either introduce or take up slack in the extended membrane. Thus, after the bather lies down on the membrane, the motor is activated so as to lower him or her into the tub, so that the bath can be begun. After the bather has finished the bath, he or she activates the motor again, but in the reverse direction, and the membrane is reeled in, thus lifting the bather back to the beginning point at the rim of the tub. As with Nowosad the system taught by Norton et al. would be difficult to introduce into a bathroom as a retrofit. Furthermore, many people, with reason, are uneasy about using electricity in close proximity to bathtubs.

[0009] Oudt (U.S. Pat. No. 5,036,555) discloses a seat on a base supported by a spring that resists being compressed by the weight of the bather. After the bather has seated himself, ballast water is introduced into the base that the total weight of bather plus ballast is more than sufficient compress the spring to the point that the bather is lowered into the bath water. When bathing is complete, the bather allows the water to drain from the bath tub, which results in the ballast water exiting the base. With the total weight on the base thereby reduced, the spring returns to its original length, elevating the bather as it does. While Oudt has the twin advantages of being easily installed in existing bathtubs, and not requiring an external power source, it is disadvantageous in that it requires the bather to remain seated while bathing. Ideally, in order to bathe properly, a bather must be able to move within the tub and not be constrained to remain in a particular spot and in a particular configuration. In addition, with the system of Oudt, there is always the possibility that the bather, in the course of bathing, may shift enough weight off the seat that the seat will rise up again, either leaving the bather behind or causing some injury.

[0010] Krumbeck (U.S. Pat. No. 5,218,727) discloses apparatus for aiding persons with limited physical ability to use a swimming pool. Incorporating two water-driven hydraulic pistons, it is intended to be mounted next to a pool. When configured to allow a person to enter the pool, it has a seat deployed along the pool's edge. When the user is perched on the seat, one of the pistons operates so as to move the person out over the water, after which the other piston permits the seat to lower into the water. When the swimming is complete, the process is reversed, with one piston lifting the seat and the other causing the seat to be moved from above the water to a position above the surface alongside the pool.

[0011] While the Krumbeck invention has the advantage of requiring no forces beyond that available from the water pressure available in the average home, its size and complexity make it completely unsuitable for installation in private bathrooms.

[0012] It appears in general that all of the prior devices aimed at assisting persons to enter and exit bathtubs have to be affixed in some way to the bathroom walls surrounding the bathtub or to the tub itself. This is a serious disadvantage, given the great variety in the shapes of walls and bathtubs and in the material that they are made of. Aside from that, there is a natural hesitancy to mar the permanent walls of a house, a serious impediment to widespread retrofitting of existing facilities.

[0013] Therefore, what is needed is a simple device to permit ambulatory individuals to take baths unattended. What is needed further is that this device avoid using electricity and that it be readily installable in conjunction with existing bathtubs, making use of motive power that is already present in the rooms housing these bathtubs. What is yet further needed is such a device that does not interfere with the bathing action of the bather once he or she is immersed in the bath water. Finally, what is needed is such a device that is free-standing in the sense that it does not need to be affixed to the bathtub or to the walls of the room in which it is to be installed and used.

SUMMARY OF THE INVENTION

[0014] It is an objective of the present invention to offer the simplest practical bathing-assist device for unattended ambulatory persons who have difficulty entering into and emerging from a bathtub. It is a further objective that the invention satisfy this goal without requiring the use of any electrical power and that it not interfere with bathing itself once the bather is seated in the bathtub. Finally, it is an objective that the device of the present invention be easily installed in existing bathroom, to be used in conjunction with existing bathtubs, and in particular that it does not require any modification of walls or of the bathtub for its installation and use.

[0015] The present invention achieves several of its objectives by being adapted to be powered by the water pressure already present in the standard home-bathroom setting. The simplicity objective is further addressed by relying on no more than a single hydraulic ram for motive power. Further, in compliance with the objective of being free-standing, the present invention is configured with its own frame, so that it does not need to be mounted on the bathroom wall or on any other wall providing an enclosure to the bathtub. The base of its frame can supported by any strong horizontal surface, including in particular the horizontal surfaces provided by the two ends of a typical bathtub. This is in contrast with many of the prior art wall-mounted devices which not only must be mounted on the wall, but tend to pull horizontally on the mounting wall, thus requiring a significant countervailing horizontal force to prevent the devices from being pulled off the wall. Also, the shift in support requirements from horizontal to vertical permits the present invention to be constructed in such a way that it can be simply lifted into place over the tub.

[0016] The shift in force direction is achieved by incorporating into the device two vertical planar elements that face one another from a distance approximately equal to the length of the tub with which the device is to be used. The bather and the elements needed to lower him or her into the bathtub are in effect hung between the planar elements, which are joined together and held apart by horizontal rods. In practice, the part of the apparatus that the bather is supported by while being lowered into, or raised out of, the tub is affixed directly to one of the vertical planar elements. Nevertheless, with the basic premise of the present invention, this support can be suspended at any point along the length of the tub.

[0017] In use, this invention normally will rely on household water pressure to lift or suspend the bather, by means of a hydraulic ram linked to the bather-support surface. Although there are a number of ways to do this it is anticipated that usually the cylinder controlling the ram will be pressurized by water taken from one of the bathroom water sources already available, such as the shower spigot. There are many ways to route the force supplied by the water pressure via the hydraulic ram. In a typical embodiment of the invention, the hydraulic cylinder is oriented vertically and configured so that when the cylinder is pressurized, the ram moves upward and when the pressure is removed from the cylinder the ram is allowed to move downward. With such an embodiment, a typical bathing session would begin with the cylinder pressurized, by the user to opening the shower tap if necessary.

[0018] The piston and associated cylinder are chosen so that the piston-face area multiplied by the available water pressure provides a force significantly greater than the weight exerted on the ram when the bather is seated on the bather support. A three-inch diameter piston with its entire face exposed to 60 psi water will resist a force of more than 380 lbs. By this choice of cylinder size, more than 95% of the target population can be accommodated. Furthermore, the concept of the invention is such it can incorporate larger cylinder/pistons, to the point where essentially all the rest of the population can also be served by the invention. In the alternative, if the bather is known to be very light in weight, a smaller cylinder can be substituted. There may, for example, be space advantages to be gained by so doing.

[0019] Although there are variants in the way that the cylinder can be used to raise and lower the bather, typically the ram head is connected to the bather support (“seat”) in such a way that when the ram is fully extended the seat is at its lowest position and when the ram is fully retracted the seat is at its highest position. When the seat is suspended in close proximity to one of the planar elements, an interface is provided to permit smooth movement of the seat and associated linkage down the face of the planar element. Ideally, each embodiment will ensure that the bather does not need to move in order to avoid contact with other portions of the apparatus as the seat is lifted to its maximum elevation. In some embodiments, this may require an offset of the cylinder from the vertical planar element.

[0020] The cylinder/piston, the linkage, and other components of the apparatus are normally chosen so that when the bather's seat is at its highest, it is situated a few inches above the rim of the bathtub and, at its lowest, is resting on the bottom of the tub with a little slack in the line, permitting the bather to move the seat completely out of the way. The seat itself can be of any of a number of designs and material. Some users may find a rigid seat, with a planar surface most comfortable, while others may desire a fabric seat preferable and yet others may like a contoured rigid seat.

[0021] In most embodiments of the invention, the linkage between the bather seat and the ram is such that the seat can be rotated while at its highest position for easy entry of the bather preparatory to bathing. Once seated, the bather then rotates and otherwise shifts the seat so that he or she is suspended directly below the ram, and held aloft by the hydraulic pressure. Next, the bather operates the valving system with which the device is equipped so as to release the pressure from the cylinder. In some embodiments, the cylinder plumbing may be arranged so that the water pressure is shifted at this point from holding the piston in its fully retracted position to providing a push to cause the ram to advance in a metered fashion in the cylinder, pushing the ram outward and the seat downward. In the most common situation, however, the arrangement will be such that the bather simply descends under gravity once the hydraulic pressure is removed. Typically, the shower tap would remain “on” and the valving used to (1) block the flow from the shower line while (2) emptying into the tub the relatively small volume of water that had been pressurizing the cylinder. Depending on particular needs, this water emptying from the cylinder can be sent directly to the bathtub drain, without need of lingering in the bathtub. This valving can be installed most simply by having two valves, one on either side of a tee, the tee leading to the cylinder. With the shower spigot “on,” closing the lower valve and opening the top valve will direct the water into the cylinder. Conversely, closing the top valve and then opening the lower valve allows the water to flow out of the cylinder, while the water from the shower line is held back. Alternatively, there are well-known valves that can achieve the same effect with a single lever, so that rotating the lever to the position that pressurizes the cylinder first closes off the drain line, then opens the house-water line to the cylinder. Similarly, moving the lever to the drain position first blocks the line carrying the house water pressure, then opens to the drain the water that is in the cylinder.

[0022] At the conclusion of the bath, the bather settles onto the seat, which may or may not have been pushed aside during the bath, and then activates the hydraulic valving so that the cylinder is again pressurized. This forces the piston into its retracted position, and the bather's seat back to its maximum height. Reversing the maneuver at the start of the bath, the bather swings his or her legs around and steps out onto the bathroom floor.

[0023] A separate class of embodiments of the present invention permits the bather to move the support seat laterally at the beginning and at the completion of the bath. This contrasts with the class of embodiment just described, wherein the point from which the line supporting the bather's seat is fixed.

[0024] In describing particular embodiments of the invention, it is understood that peripheral structures of the embodiment will be adapted to fit the specific bathtub environment in which the embodiment is installed. For example, the older (but not oldest) style of porcelain bathtub is usually installed in a bathroom so that it is bordered on two or three sides by bathroom walls. (The oldest style stands on its own legs, but also generally along one wall of the bathroom.) In recent decades, plastic bathtub/shower modules have been introduced that contain their own walls on three sides. Even the standard porcelain tub that is not part of an enclosing module can have variants in its installation. For example, it is not uncommon to have a half-wall of tile superimposed on the bathroom wall surrounding the tub. This results in a ridge extending around the niche and providing another support surface on which to place the frame of the bathing-assist apparatus.

[0025] Because of the simplicity of the present invention, any of its embodiments can be installed in a wide range of bathtub environments, as will be clear to persons familiar with the nature and purposes of the invention after reading the detailed description set out below for the preferred embodiment of the invention installed in a particular bathtub environment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a perspective not-to-scale view of the preferred embodiment, showing the apparatus resting on the two endwalls of a bathtub, the bathtub being positioned in a three-walled niche without any tile; for clarity, the bathroom wall parallel to the head (spigot-end) of the bathtub is not shown.

[0027]FIG. 2 is a not-to-scale side view of the apparatus shown in FIG. 1, in which a bather representing late middle-aged 90th-percentile male is seated; the bathroom wall parallel to the head of the bathtub, missing from FIG. 1, is shown.

[0028]FIG. 3 shows a different embodiment of the invention, one that permits the bather to control lateral movement of the support seat between the bathing position and the bathroom floor alongside the bathtub.

[0029]FIG. 4 depicts the details of the lateral conveyance device shown in FIG. 3.

PREFERRED EMBODIMENT OF THE INVENTION

[0030]FIG. 1 shows the preferred embodiment of the bather-assist device 1000 in conjunction with a bathtub 1. For the purposes of definitiveness, a particular environment is shown for the bathtub 1, where the bathtub 1 is surrounded on three sides by bathroom walls designated here as a back bathroom wall 40, a head bathroom wall 50, and a foot bathroom wall 20. This niche structure is not preferred in any way itself, and the device 1000 can be introduced to any of a variety of tub environments, as will be seen from this discussion. With continuing reference to FIG. 1, it can be seen that a flexible-fabric bather's seat 6 is linked through a seat harness 22 and a seat yoke 7 to a hydraulic ram 10. The ram 10 in turn is rigidly coupled to a piston (not shown) enclosed within a cylinder 5. In the preferred embodiment, the cylinder 5 is four inches in diameter. The cylinder 5 is designed to be reversibly pressurized by the local water supply, for which purpose the internal volume of the cylinder 5 it is attached to a cylinder line 92. The cylinder line 92 leads to a tee-intersection with a valve system 8, the tee intersection being located between an upper valve controlled by upper lever 38 and a lower valve controlled by a lower lever 37. When the upper lever 38 is open, it permits water from a water line 91 to flow through the upper valve and when the upper lever 38 is closed, it stops flow from the water line 91, the water line 91 normally containing house-water under the prevailing household water pressure. The source of this water pressure in water line 91 is a shower spigot 11 to which the water line 91 is connected through flexible joinder line 93 in the preferred embodiment.

[0031] Similarly, the lower valve is open or closed depending on the position of the lower lever 37. When the lower valve is open, the inter-valve length of waterline is open to a drain line 9, which empties into the bathtub 1. With both the upper lever 38 and the lower lever 37 in their respective open positions, water will flow directly from the water line 91 into the bathtub 1 through the drain line 9. However, when the lower lever 37 is closed and the upper lever 38 is open, the water flows only into the cylinder 5.

[0032] When the water is thus directed to the cylinder 5, the cylinder 5 quickly reaches the full pressurize, typically 60 psi or higher, and the ram 10 is held firmly at its maximum height. This ensures that the seat 6 is also held at its maximum height with full supporting force. With the diameter of the cylinder 5 four inches and the water pressure 60 psi, this supporting force is somewhat over 750 lbs. In many homes, the water pressure is considerably higher. So it is clear that persons up to 400 lbs, well into the 99th-percentile of weight can be accommodated with a broad margin of safety associated with the hydraulic cylinder. In constructing the rest of the device, all of the components that take part in the chain supporting the bather should be designed so as not to lessen the overall capacity of the hydraulic component.

[0033] With reference to both FIG. 1 and FIG. 2, one can see how the seat harness 22 is connected to two ends of a yoke 7. The yoke 7 is curved and configured with the rest of the linkage so that its curve normally lies in a horizontal plane. The yoke 7 is made of steel in the preferred embodiment and the end of the ram 10 is welded to it at the rearward extremity of the yoke 7. The shape of the yoke 7 is determined by the need to ensure that the seat 6 and a bather 100 occupying the seat 6 are positioned so that they do not scrape against any other components of the device during the raising and lowering operations. Because of the force moment that this places on the coupling between the ram 10 and the yoke 7, it is essential that this coupling be durable; a good weld joint is sufficient for this purpose. Extending rearward from the rearmost extremity of the yoke 7 is a stand-off stub 71 that terminates in a roller assembly 21. The roller assembly 21 has a rear surface that rolls along a backstop 25 as the seat 6 moves up and down. The backstop 25 is a large planar element that in the preferred embodiment extends the full width of the bathtub 1 and defines the maximum vertical extent of the device 1000 itself. As can be seen in both FIG. 1 and FIG. 2, the cylinder 5 is hung with its longitudinal axis vertical from a metal mount 26 that is affixed to the backstop 25 The backstop 25 in turn is rigidly affixed to a head H-frame 34. The head H-frame 34 in combination with an identical foot H-frame 33 forms an extended frame from which all components of the device 1000 are suspended or otherwise affixed. This extended frame can be lifted completely away from the bathtub 1, and provides all of the support needed for the functioning of the device 1000, thus obviating the need for making attachments of any kind to bathroom walls or to the bathtub 1.

[0034] The head H-frame 34, rigidly affixed to the backstop 25 is bound to, and held apart from, the foot H-frame 33 by a top rear spacer 28, a middle rear spacer 36, a bottom rear spacer 35, an upper front spacer 29, and a lower front spacer 23. All of these spacers have a standard-design telescoping capacity so that their lengths can be varied and in that manner the overall length of the device 1000 can be varied so as to fit bathtubs of varying lengths. On each of the spacers is a line symbolizing the telescoping capacity. Thus a top rear spacer telescoping junction 281 is seen on the top rear spacer 28. In the bathroom environment presented in connection with this discussion of the preferred embodiment, the head H-frame 34 will be positioned flush with the head bathroom wall 20 and the foot H-frame 22 flush with the foot bathroom wall 50. The head H-frame 34 together with the backstop 25 are supported atop the bathtub 1 at its foot end adjacent to the foot bathroom wall 20. Similarly, the foot H-frame 33 is supported atop the bathtub I at its head end adjacent to the head bathroom wall 50, as before, “head” referring to the end closer to the spigots of the bathtub 1. The spacers separating and joining the head H-frame 34 and the foot H-frame 33 serve to counter the moment of force tending to pull the backstop 25 forward when the bather 100 is seated in the seat 6, and suspended by the hydraulic forces. In the preferred embodiment all spacers are metallic, either tubes or rods. Each of the spacers is affixed at one end to the backstop 25 and at the other end to the head H-frame 33, which, unlike the foot H-frame 34, the shape of cannot be seen because of the presence of the backstop 25, is shown in detail in FIG. 1. The H-frame 33 has a first leg 32, a second leg 31 and a crosspiece 30 connecting the first leg 32 to the second leg 31.

[0035] The ram 10, to which the seat yoke 7 is rigidly attached, rotates freely about its vertical axis, thereby allowing the seat 6 to be swung around to face a bathtub front wall 4, facilitating transfer between the bathroom floor and the seat 6. FIG. 2 shows the bather 100 in the seat 6 with the seat 6 positioned partway between its two extreme elevations. The bather 100 depicted here has the proportions of a large man (90th percentile) in the age range most likely to find the present invention of use.

[0036] Once seated on the seat 6, the bather 100 rotates the seat 6 until he is facing the end of the tub I where the spigot 11 is located and the valve system 8 is within easy reach. The pivoting of the seat 6 is facilitated in part by the roller assembly 21, as it moves smoothly across the backstop 25 while the yoke 7 and ram 10 are rotating. It is assumed that the upper valve is open and the lower valve closed so that the water pressure is serving to pressurize the cylinder 5. Once seated securing in the center of the foot end of the bathtub 1, the bather 100 grasps the upper lever 38 and turns the upper valve off, thus cutting off the connection between the cylinder 5 and the water pressure. Next, the bather 100 grasps the lower lever 37 and opens the lower valve, thus connecting the water in the cylinder 5 to the cylinder drain tube 9. As the water bleeds from the cylinder 5, out into the cylinder drain tube 9, the ram 10 gradually extends under the downward force exerted by the weight of the bather 100 until the seat 6 is supported by a bottom bathtub surface 3. With the seat 6 and bather 100 so supported, the bather 100 can easily bunch the seat 6 up and move it to one side, so that it does not interfere with bathing. The bather 100, now seated or supine on the bottom bathtub surface 3, may bathe in a normal manner.

[0037] Once bathing is completed, the bather 100 spreads the seat 6 so that he or she is again seating squarely on it. Then the bather 100 grasps the lower lever 37, turning it to its closed position and then turns the upper lever 38 to its open position. This repressurizes the cylinder 5 and causes the ram 10 to be retracted, returning the seat 6 and the bather 100 to a position above the top of the bathtub 1.

[0038] Because of the structure described above, it can be seen that this embodiment of the invention requires no alteration of the walls of the tub area, nor does it require permanent mounting of any elements on the walls. The invention may be easily made to fit a variety of domestic bathtubs be altering the width and length of the backstop 25, and altering the lengths of the spacers and thus the separation of the foot H-frame 34 from the head H-frame 33. In the preferred embodiment, the backstop 25 and members of the H-shaped frame 33 are made of plywood coated with a water-proof plastic material.

[0039]FIG. 3 shows a variant on the preferred embodiment, wherein the arcuate yoke 7 is replaced with a straight seat beam 70, and a lateral conveyor 500 is added, the lateral conveyor 500 enabling the bather 100 to always sit directly beneath the cylinder 5. Instead of being pivotably affixed to the backstop 25, the cylinder 5 is now pivotably affixed to a cylinder support plate 150 and the cylinder support plate 150 is rollingly affixed to a channel bracket 600. In turn, the channel bracket 600 is rigidly affixed to the backstop 25 by a rear bracket support 601, a middle bracket support 602, and a front bracket support 603 in a cantilevered configuration.

[0040] The lateral conveyor 500 includes a pull-rope 550. One end of the pull-rope 550 is affixed to a distal end of the channel bracket 600 as can be seen in FIG. 3. The pull-rope 550 then passes through a proximal pulley 551 affixed to the cylinder support plate 150 after which the pull-rope 550 passes through a distal pulley 552, and back to a proximal end of the channel bracket 600. The pull-rope 550 is of such a length that it is relatively taut when the cylinder 5 is located near to the proximal end of the channel bracket 600, but nevertheless remains graspable by the bather 100 when the bather 100 is seated in the seat 6, as shown in FIG. 3 to be grasping the pull-rope 550. When the bather 100 is located outside the bathtub 1 and pulls the pull-rope 550 so as to introduce slack the pull-rope 550 will pull the cylinder support plate 150 and everything attached to it toward the back bathroom wall 40. In this way, the bather 100 pulls himself from a position above the floor outside the bathtub 1 to a position above the inside of the bathtub 1, at which point he can lower himself toward the bathtub bottom surface 3 just as he did in the embodiment depicted in FIG. 1 and FIG. 2. Note that because of the two-pulley system a mechanical advantage is introduced so that the required force is even less than it would otherwise be.

[0041] When the bather 100 has finished bathing, returned to the seat 6, and repressurized the cylinder 5 the seat 6 rises lifting the bather 100 to a position above the bath water. At that point, the bather 100 can move back to a position above the floor outside of the bathtub 1 either by pushing on the back bathroom wall 40, or by pulling on that part of the pull-rope 550 that is affixed directly to the proximal end of the channel bracket 600. Then, with the seat 6 once again directly above the floor outside the bathtub 1, the bather 100 simply walks away.

[0042]FIG. 4 is a close-up of the some of the details of the lateral conveyor 500. Central to the operation of the lateral conveyor 500 is the ease with which the cylinder support plate 150 can be moved along the channel bracket 600. There are a number of ways to achieve ease of movement; the preferred one being to couple the cylinder support plate 150 to the channel bracket 600 through a set of off-the-shelf rollers 800, as shown in FIG.

[0043] The recital of the details of a particular embodiment of the invention is not intended in any way to limit the scope of the invention. Those skilled in the art can see that the Summary and Preferred Embodiment discussions suggest many variants on the structures depicted herein. 

I claim:
 1. Apparatus for assisting a bather to enter and to exit a bathtub, said device comprising a) a hydraulic cylinder configured to lower and raise said bather on demand using only household water pressure; b) valving for linking said household water pressure to said cylinder, said valving being configured so as to allow said bather to pressurize and depressurize said cylinder; wherein said apparatus includes support structure for suspending said cylinder, and wherein said support structure is placeable on upper surfaces of said bathtub, requiring no other mounting or affixing elements in order for said apparatus to be installed and ready for use.
 2. The apparatus claimed in claim I wherein said bather is lowered and raised by lowering and raising a bather support surface, said bather support surface being directly linked to an hydraulic ram extending from said cylinder.
 3. The apparatus claimed in claim 2 wherein said cylinder is deployed so as to be oriented vertically when said apparatus is installed on said bathtub.
 4. The apparatus claimed in claim 3 wherein said valving includes a hand-operated valve that interruptedly links a household water line to a cylinder water line, said household water line being connectable to a source of household water pressure and said cylinder water line being connectable to said cylinder for pressurizing said cylinder.
 5. The apparatus claimed in claim 4 wherein said valve has a plurality of positions, including a pressurizing position that causes a linkage to exist between said household water line and said cylinder water line, and a depressurizing position that interrupts said linkage and causes a depressurization of said cylinder.
 6. The apparatus claimed in claim 5 configured such that when said cylinder is pressurized said ram applies an upward force to said seat sufficient to lift said bather and that when said cylinder is not pressurized said seat is allowed to descend.
 7. The apparatus claimed in claim 6 wherein said support structure includes a head frame, a foot frame, and a backstop, wherein said head frame is joined to and separated from said foot frame by horizontal spacers and a back stop is affixed rigidly to said head frame.
 8. The apparatus claimed in claim 7 wherein, after said apparatus is installed, said cylinder is positioned directly above said bathtub with said ram extending downward from said cylinder.
 9. The apparatus claimed in claim 8 wherein said cylinder is pivotably affixed at a top end thereof to said backstop.
 10. The apparatus claimed in claim 7 also comprising a lateral conveyor for conveying said cylinder between a outside position and an inside position, said outside position placing said bather above a floor surface next to said bathtub and said inside position placing said bather above said bathtub.
 11. The apparatus claimed in claim 10 wherein said conveyor includes a roller-support channel, a roller unit, and a cylinder top plate, said support channel being rigidly and horizontally attached to said support means, said cylinder top plate linking a top of said cylinder to said roller unit, said roller unit being coupled rollingly to said channel.
 12. The apparatus claimed in claim 11 wherein said conveyor also includes a bather-operated translating means, whereby said bather can cause said cylinder to translate between said inside position and said outside position.
 13. The apparatus claimed in claim 12 wherein said translating means is a combination of a pull-rope and a plurality of pulleys.
 14. The apparatus claimed in claim 13 wherein a first end of said pull-rope is affixed at a distal position of said channel, a second end of said rope is affixed at a proximal position of said channel and between said first end and said second end said rope passes in sequence through a proximal pulley and a distal pulley.
 15. The apparatus claimed in claim 14 wherein said rope is relatively taut when said cylinder is located at said outside position and deployed so that when said bather pulls down on said rope so as to introduce slack in said rope, said rope pulls said cylinder toward said inside position.
 16. Bathing assist apparatus for use in conjunction with a domestic bathtub and household water supply, said apparatus comprising a support structure, a hydraulic lift device, a pressurizing circuit, a bather seat, an arcuate seat yoke, wherein said support structure includes a head frame, a backstop, a foot frame, a plurality of adjustable-length spacers and is constructed so that said head frame and said foot frame are parallel to one another, joined together by said plurality of spacers, and configured so that said apparatus is installable said bathtub by resting said head frame on a head rim of said bathtub and said foot frame on a foot rim of said bathtub, said spacers being adjusted in length to fit said bathtub, wherein said hydraulic lift device is a hydraulic cylinder containing a hydraulic ram wherein said hydraulic ram is retracted into said cylinder with a force of several hundred pounds upon said cylinder being pressurized with said household water supply, wherein said cylinder is pivotably affixed at a top end thereof to said backstop, said backstop being rigidly mounted on said head frame, wherein said yoke is connected to said ram and said seat is flexibly coupled to said yoke, and wherein said pressurizing circuit includes a household water line connected at a first end to a hand-operated valve unit and connectable at a second end to said household water pressure, a bathtub line connected only to said valve unit and otherwise open, a cylinder water line running between said valve unit and said cylinder, wherein said valve unit has a plurality of positions, one of which directly connects said household water line to said cylinder line, one of which connects said household water line to said bathtub line, and one of which connects both said household water line and said cylinder water line to said bathtub line.
 17. Bathing assist apparatus for use in conjunction with a domestic bathtub and household water supply, said apparatus comprising a support structure, a hydraulic lift device, a pressurizing circuit, a bather seat, a bather conveyor, and a conveyor motivating device, wherein said support structure includes a head frame, a backstop, a foot frame, a plurality of adjustable-length spacers and is constructed so that said head frame and said foot frame are parallel to one another, joined together by said plurality of spacers, and configured so that said apparatus is installable said bathtub by resting said head frame on a head rim of said bathtub and said foot frame on a foot rim of said bathtub, said spacers being adjusted in length to fit said bathtub, wherein said hydraulic lift device is a hydraulic cylinder containing a hydraulic ram, wherein said hydraulic ram is retracted into said cylinder with a force of several hundred pounds upon said cylinder being pressurized with said household water supply, wherein said conveyor includes a roller-support channel, a roller unit, and a cylinder top plate, wherein said channel is rigidly affixed to said backstop and cantilevered so as to extend several feet outside of said bathtub when said apparatus is installed in said bathtub, wherein said roller unit is coupled rollingly to said channel and to said cylinder top plate, said top plate being pivotably connected to said cylinder, wherein said motivating device includes a pull-rope, a distal pulley, and a proximal pulley, said pull-rope being affixed at a distal end of said channel and at a proximal end of said channel, and running through said distal pulley and said proximal pulley.
 18. The bathing assist apparatus claimed in claim 17 wherein said seat is made of flexible fabric and is flexibly connected to a straight seat yoke, said seat yoke in turn being connected to said ram.
 19. The bathing assist apparatus claimed in claim 18 configured so that, when said apparatus is installed, said cylinder is pressurized said seat is pulled upon and when said cylinder is not pressurized said seat is allowed to move downward under the force of gravity.
 20. The bathing assist apparatus claimed in claim 19 wherein said backstop, head frame, and foot frame are made of wood and said spacers are made of steel. 